Beverages such as beer and soft drinks are frequently packaged in cans which are marketed to consumers in groups termed "multipacks," with the group of six cans termed the "six pack" being the most popular. Six packs are typically shipped from the producer to the retailer in open-topped, low-sided corrugated cardboard cartons, four six-packs to a carton. The carton of six packs is often wrapped with a plastic shrink wrap to hold the six packs in place.
The six cans of a six pack are typically arranged to form a rectangular two-row by three-column array held together with a flexible plastic holder termed a "top grip" which has loops into which the tops of the cans fit. The top grip generally maintains a separation of a few millimeters or so between the top portions of adjacent cans in the six pack.
Although the top grip generally maintains a separation between the top portions of adjacent cans in a six pack, the flexibility of the top grip permits adjacent cans to touch near the bottom of the cans. Touching of adjacent cans gives rise to serious problems in the shipment of six packs of cans. Motion during shipment frequently causes adjacent cans which are touching to rub one another at the points of contact. Such rubbing often wears away the graphics or labelling on the can. The resulting worn spots on the cans are unsightly and reduce the appeal of the product to potential customers. Moreover, adjacent cans which touch can rub one another to such an extent that a wall of one of the cans wears completely through during shipment. When the wall of a can wears through, liquid in the can leaks out. Even a single can which leaks in a shipment of cans of beverage represents a serious loss, since health codes often require that an entire shipment be scrapped even if any leakage occurs.
Recently, an economical spacer tray for containers such as cans or bottles has been developed which effectively maintains a proper spacing between lower portions of cans or other containers loaded in the tray. The new spacer tray is disclosed in U.S. patent application Ser. No. 048,437, filed May 9, 1987 ("the '437 application"), which application is hereby incorporated by reference in the present application. The '437 application should be consulted for details concerning various embodiments of the spacer tray. Two preferred embodiments of the spacer tray which may be used in the loading machine of the present invention are described briefly in the following paragraphs.
Broadly, a first preferred embodiment of the spacer tray is adapted to be used with four six-packs of cans and will be termed the "six-pack spacer tray" below. The six-pack spacer tray is formed of a moldable plastic sheet material and is shaped to provide twenty-four can-bottom receptacles disposed in a four-row by six-column array. Each can-bottom receptacle is shaped to receive at least a part of a bottom portion of a can. A can-spacer wall is located between each pair of adjacent can-bottom receptacles to maintain the bottom portions of the cans seated in the adjacent can-bottom receptacles spaced apart from one another. Fifteen can-loading-guide-pin caps are formed in the spacer tray in a three-by-five array. Each can-loading-guide-pin cap is located centrally of four can-bottom receptacles whose locations are defined by the intersection of a pair of adjacent rows of receptacles with a pair of adjacent columns of receptacles. Each can-loading-guide-pin cap projects generally upwardly from an upper side of the spacer tray and, as explained in more detail below, is shaped to guide bottom portions of cans into the can-bottom receptacles during loading of the spacer tray. The spacer trays are shaped to nest one inside the other to form stacks of nested spacer trays. Four six packs of cans can be loaded in the spacer tray with the bottom portions of the cans seated in the twenty-four can-bottom receptacles of the spacer tray. The can-bottom receptacles around the perimeter of the six-pack spacer tray surround only partially the bottom portions of cans seated in the receptacles. The six-pack spacer tray is dimensioned so that the cans in the can-bottom receptacles around the perimeter of the spacer tray extend outwardly of the perimeter.
A second preferred embodiment of the spacer tray is adapted to be used with loose cans, i.e. cans not connected by top grips to form multipacks, and will be termed below the "loose-can spacer tray." The loose-can spacer tray is generally similar to the six-pack spacer tray described above. In particular, the loose-pack spacer tray has twenty-four can-bottom receptacles and fifteen can-loading-guide-pin caps at essentially the same locations as the can-bottom receptacles and can-loading-guide-pin caps of the six-pack spacer tray. However, the over-all lateral dimensions of the loose-can spacer tray are greater than the lateral dimensions of the six-pack spacer tray to permit certain of the can-bottom receptacles around the perimeter of the spacer tray to surround the bottoms of the cans more completely to hold the loose cans in position laterally more securely.
After being loaded with cans at a bottling facility, spacer trays of either the six-pack or the loose-can type are ordinarily enclosed with a heat-shrinkable plastic film which is caused to shrink by heating. The resulting taut shrink-wrap covering holds the cans in the spacer trays.
Commercial bottling operations for soft drinks or other beverages typically produce cans of beverage at an extremely high rate. Measured in terms of twenty-four can case loads, it is not uncommon for bottling operations to produce filled cans at a rate of 60, 80 or even 100 cases per minute. A need exists for a machine to load the spacer trays described above at such high speeds for commercial bottling operations.